OK, the basic story is that if I leave the 'leccy turned on all is well, however if I switch the PC off at the wall there's a 50% chance that it will trip the 'leccy when I turn the supply back on. I'm thinking either high initial power draw or faulty PSU, I'd rather it wasn't the latter since it's less than a year old.

Any ideas?

Can't see the PSU coping if it pulled enough power to trip the electricity, so my money would be a duff PSU. But I aint no expert.

That's what I thought....stupid thing. I've got a 700W PSU powering a single gfx card and quad-cpu, it's not a cheap brand either so I'd be mightily peeved.

Would it not be under some kind of warranty or guarantee? Even if there's nothing saying that there is, a call to the supplier/manufacturer might be worth it...

Oh it should be under 12 months warranty still, and even if it wasn't, I'd be breathing down the retailers neck with S.14 of the Sale of Goods Act ("lasts for a reasonable time").

I just don't want the hassle of sending it back etc and then having to "plumb-in" a new PSU. Plus that leaves me without my blessed PC for a while...

Are you using the cable that came with the PSU with the right size fuse?

I should be, though that's worth checking! I'll report back.

I'm no electrician but a couple of years ago we had a similar problem with our new shower tripping the main fuse box when switched on, or while on and even when turned off. From what I remember we had the apparently correct rated fuse in the fuse box and even changed it with a same rated spare fuse. In the end from what I recall was we upped the fuse from 40 to 45 amp - I can't remember exactly - but this fixed the problem. I'm not saying this is the solution but it may help. I do however caution you about having incorrect rated fuses fitted for obvious reasons.

Well the plug for the PC has a 13A fuse in it, which seems correct? I have no way of telling if it's still the original cable - I have so many kettle leads lying about the place.

It's done this in two houses now, so I don't think it's a problem with the wiring in the house (unless I just have really bad luck).

The fuse in the plug should blow before the ring main does! Either that or your ring main has too small a capacity before it trips. If you are using a 4-way extension, I'd also rule that out as well. I've had one go funny before and blow the ring main.

I *think* I might have solved it. I had re-wired my 4870 incorrectly after swapping-out a friend's card, it was drawing power from the wrong part of the PSU.